The present invention relates to a novel process for preparing 5-hydroxyhydantoin.
5-Hydroxyhydantoin, as mentioned below, is an important compound which can be converted into 5-(p-hydroxyphenyl)hydantoin, according to the process described in Japanese Unexamined Patent Publication No. 138560/1979, which compound is a starting material for p-hydroxyphenylglycine useful for synthesis of semisynthesized penicillin or cephalosporins.
There have been known many processes for preparing 5-hydroxyhydantoin. Examples of these processes are, for instance, a method wherein alloxan is treated with alkali such as an alkali metal hydroxide or an alkaline earth metal hydroxide to give alloxanic acid, followed by decarboxylation under heating in its aqueous solution (see Berichete der Deutschen Chemischen Gesellschaft, 54B, 1802 (1921)), a method wherein parabanic acid is reduced with potassium borohydride (see Bulletin de la Societe Chimique de France, 942 (1971)), a method wherein glyoxylic acid and urea are reacted in an acidic medium (see Tetrahedron, 33, 1191 (1977)), a method wherein hydantoin is oxidized with lead tetraacetate or alkylperoxide (see Japanese Unexamined Patent Publication No. 75473/1989).
However, the methods using alloxan, parabanic acid or glyoxylic acid are not satisfiable, because the starting materials are expensive. The method wherein hydantoin is oxidized has the problem that dangerous lead tetraacetate or alkylperoxide must be used.
An object of the invention is to provide a useful process for preparing 5-hydroxyhydantoin from an inexpensive starting material.
This and other objects of the present invention will become apparent from the description hereinafter.